An ad-hoc network, which is constituted by terminal apparatuses, is an independent distributed network without relying on any base station apparatus or wired network. In the ad-hoc network, each of the terminal apparatuses is given an equal role and function, and the terminal apparatuses exchange information with each other through multi-hop routing. Such routing methods in the ad-hoc network include a table-driven method, an on-demand method, and a hybrid method. In the table-driven method, each terminal apparatus maintains a routing table that associates the final destination of a packet signal with next-hop destinations thereof. Also, each terminal apparatus determines a next-hop destination from the destination of a packet signal by referencing the routing table. Examples of the table-driven method are DSDV (Destination Sequence Distance Vector), WRP (Wireless Routing Protocol), CGSR (Clusterhead Gateway Switch Routing), and OLSR (Optimized Link State Routing).
In the on-demand method, a terminal apparatus, which generates source information, finds a route through which to arrive at a target terminal apparatus, when it requests a transfer of the packet signal. The terminal apparatus generating the source information first transfers the packet signal used for the inquiry, by flooding the packet signal. Thereby, a reverse-direction route toward the source-information generating terminal apparatus is learned. At the same time, the source-information generating terminal apparatus also replies to the target terminal apparatus that has received the packet signal used for the inquiry. Based on the route found as above, the packet signal is transferred from the source-information generating terminal apparatus to the target terminal apparatus. Examples of the on-demand method are AODV (Ad hoc On demand Distance Vector), DSR (Dynamic Source Routing), TORA (Temporally Ordered Routing Algorithm), RDMAR (Relative Distance Micro-discovery Ad hoc Routing protocol), and ABR (Associativity-Based Routing). The hybrid method is a method combining the table-driven method and the on-demand method (See Non-patent Document 1, for instance).
In the ad-hoc network, a technique is suggested which simplifies the setting of terminal apparatuses. A predetermined terminal apparatus holds communication setting information, and a tag is held closely over an IC card reader/writer mounted to this terminal apparatus. As a result, the IC card reader/writer communicates with the tag through a noncontact communication and thereby transmits the communication setting information. Also, a procedure reverse to that described above is performed between the tag and an IC card reader/writer mounted on another terminal apparatus and thereby the communication setting information is transmitted to the another terminal apparatus (See Patent Document 1, for instance).